The opera is about the principles of music, such as harmony and structure, and the composers Haydn, Mozart, and Beethoven, all immersed in an opera buffa. The opera is full of witty music theory banter and features characters named after chords at the basis of Classical harmony, such as Dominant, Tonic, and Subdominant. The score includes direct quotes from Haydn, Mozart, and Beethoven, and some say it's subtle, sly, and vividly colorful.